Molded structural parts for compressors



July 27, 1965 K. v. VALBJQRN MOLDED STRUCTURAL PARTS FOR COMPRESSORS Filed Aug. 17, 1962 2 Sheets-Sheet 1 July 27, 1965 K. v. VALBJQRN MOLDED STRUCTURAL PARTS FOR COMPRESSORS 2 Sheets-Sheet 2 Filed Aug. 17, 1962 United States Patent 3,197,127 MQLDED STRUCTURAL PARTS FQR CQMPRESSGRS Knud V. Valhjarn, Nordborg, Denmark, assignor to Danfoss veil. lug. M. Clausen, Nordborg, Eenmarlt, a company of Denmark Filed Aug. 17, 1962, Ser. No. 217,767

Claims priority, application Germany, Aug. 19, 1961,

1) 36,845 17 Claims. (Cl. 23il-232) This invention relates to cast or molded structural parts for compressors, and is more particularly concerned with cast of molded parts consisting of a cylinder or cylinder head with silencer chambers laterally connected to it.

In the case of motor compressors for small refrigerating machines, it is known, for purposes of economy of connecting lines, to provide additional structural parts and, for greater economy in the use of space, to provide silencer chambers, in direct communication with the cylinder or cylinder head of the compressor. The chambers run in the direction of the cylinder diameter, starting from one end surface of the structural part up to the level of the opposite end surface. The open end of each chamber is sealed with a covering plate.

In the casting or molding of such a structural part, a different mold core is used for each chamber, and this greatly adds to the cost of manufacture. In particular, this factor conflicts with the intention of providing more than one silencing chamber in each projection or extension. Since a taper of some 5 must be taken into account, the intermediate wall between two neighboring chambers becomes relatively thick at its upper end. This is true in particular of the upper end of the wall between the silencing chamber and the cylinder cavity. The increased amount of material required causes added weight and expense. A very important further disadvantage in small refrigerator machines is the fact that known silencing chambers cannot be readily reached, yet small amounts of dirt in the refrigerating machines central circuit can interfere with the proper operation of the machine.

It is accordingly an object of this invention to provide a construction for a compressor which avoids the foregoing drawbacks and disadvantages.

In accordance with the invention, there is provided a structural member or unit that is characterized by the fact that it has a separating wall extending from the cylinder and on either side of this wall, and extending in opposite directions, are provided silencing chambers which open outwards. The silencing chambers so formed are only half as high as in known constructions. They can be manufactured without difiiculty by means of the mold proper without the use of any core. In addition, there is a saving in casting material because on both sides of the separating wall or partition, access can be had to the cylinder, and because a thinner partition is obtained between two chambers in the same direction. For a given chamber volume the cost of producing the structural unit of the invention is only 75% of the cost of producing known structural units. Owing to their lesser depth, the silencer chambers of my construction can be more easily cleaned. Furthermore, the structural unit can be produced by means of molding trays (according to the Croning process) so that, from the start, a cleaner surface is achieved.

A further essential feature is the fact that at least two silencing chambers are produced in each lateral extension. Yet, without adding to the cost of the casting process, more than two silencing chambers can be provided on one or both sides of the cylinder, since for this purpose no additional cores or blocks are needed. Con- 3,197,127 Patented July 27,1965

ICC

sequently, without any added expense, a greater silencing effect and a lower frequency limit can be attained. If on each side of the partition only a single silencing chamber is provided, the connecting of the chambers is no problem. If several silencing chambers are provided, it is advisable that one chamber on one side of the partition should at least partially overlap two chambers on the other side of the partition. In this manner, it is possible to establish connection between the chambers by parallel bores on the same side.

i In one embodiment, the connecting bore runs only through the partition, and Within the bore is disposed a tube that is longer than the thickness of the partition. Extension of the restrictor, according to known laws, produces an improved silencing efiiect and a reduction in the frequency limit.

According to another embodiment, the connecting bores pass through an extension or prolongation that is connected to the chamber wall and terminates just beneath its frontal surface. In this case, the connecting bore is per se of such length that it serves as the throttler or restrictor. Where there are several chambers it is also possible to effect connection by means of parallel bores from the same side.

Since the structural unit according to the invention is thus relatively easy to cast or mold, there are no problems as regards casting the structural unit as a single member with the motor mount. Thus, in the case of a small refrigerating machine, nearly all of the fixed castable structural elements can be united in a single casting. If the silencer chambers are set upon the cylinder, then only the cylinder head has to be added. If, however, the silencer chambers are set upon the cylinder head, only the cylinder has to be added.

The closing of the open sides of the silencing chambers is easily effected. For example, the open ends of the chambers can in each case be covered over with a single cover-plate for each side of the partition. In many cases this cover-plate can actually be the motor or engine mount or some other structural element.

For the securing of the plates many possibilities are afforded. As an example, they can be pressed on or fastened on. It is advantageous to secure the plates on either side of the structural unit by means of common fastening devices, such as screws, or bolts. If the motor mount is employed as a second plate, the first plate can be secured by means of the same bolts used to secure the motor mount, so that the structural unit is itself attached to the motor mount.

Additional features and characteristics of the invention will be apparent from the following detailed description of several embodiments, taken in connection with the accompanying drawings, wherein:

FIG. 1 is a plan view of the engine mount with the structural unit according to the invention bolted thereon, the unit containing the compressor cylinder and silencer chambers;

FIG. 2 is a view of the structural unit as seen from below;

FIG. 3 is a side view of the structural unit, in part along the section line AA of FIG. 2;

FIG. 4 is a plan View of the structural unit, with associated parts removed; and

FIG. 5 is a partial sectional view taken generally along the line of BB of FIG. 2.

In FIG. 1 the motor mount 1 of a small refrigerating machine is shown, in which the center bore 2 constitutes the bearing for the motor crankshaft (not shown), said mount being connected with the stator of the electric drive motor by means of bolts 3. On mount 1.the structural member or unit 4 is secured by means of screw- 9 bolts 5, 6. This structural unit contains central cylinder bore 7 and, in each lateral extension 8, three'silencer chambers 9, 1t) and 11. Not shown, in order to simplify the description, is the cylinder head which, together with the customary parts, such as'the valve plate, packing, and the like, is screwed onto the frontal surface 12 of structural unit 4, for which purpose the threaded holes 13 are provided. Extending away from cylinder 7 is a partition wall 14 which separates the silencer chambers 9 and 11, which open toward the motor mount, from silencer chamber 10, which opens in the opposite direction. When the unit is assembled, the chambers 9, 11 are sealed olf by the engine mount 1 proper. Chamber is provided with a cover 15 which is secured by bolt 5.

In the illustrated embodiments, given solely by way of example, the silencer chambers 9, 1t) and'll are connected in series, with chamber 10, however, being in direct connection with the suction chamber through the agency of an added suction channel. For this purpose, a suction bore 16 leading to chamber 9 and a suction bore 17 leading to chamber 10 are provided. The connection between chambers 9 and 10 is provided by means of the bore 18, and the connection between chambers 19 and 11 is established by bore 19. Chamber 11 is' connected with frontal side 12 and with the cylinder head by means of bore 20. For purposes of introducing screw-bolt 5, bores 21, and for screw-bolt 6, bores 22, are provided.

All of the bores can be produced in only two settings of the structural member. In the setting in which the inside cylinder surface 7 is being worked, the suction bores 16 and 17, the outlet bores 28, and the threaded holes 13 can be made. In awork position that is at right angles thereto, where the boring meansare operating in the direction of the side that is shown in FIG. 4, the connection bores 18 and 19, and the bores 21 and 22 for the screw-bolts are made.

To improve the operation of the silencer, tube sections 23 and 24. can be inserted in the suction openings and in the connection bores. A similar effect is achieved with connection bore 18 (FIG. 5) in that the chamber wall is given an extension 25 that terminates just short its frontal surface, through which extension the connecting bore is run.

The illustrated manner of construction is only. an'example, which can be varied in many ways, e.g. in the number of silencer chambers, in the manner of their connection, in the manner of their sealing, and the like. Instead of locating the silencers in extensions of the cylinder, by the application of the concept of the invention they can also be located in the cylinder head. If the structural unit is cast in one piece with the motor mount, the silencer chambers opening towards the motor will similarly be sealed with separate cover-plates. The two plate-like covers 15 for sealing of the chambers 19 can also be replaced by a single common cover-plate.

It will also be understood that various other changes and modifications may be made in the embodiments described above and illustrated in the drawings without departing from the scope of the invention as defined in the appended claims.

It is intended, therefore, that all matter contained in the foregoing description and in the drawings shall be interpreted as illustrative only and not as limitative of the invention.

What I claim and desire to secure by Letters Patent is:

1. A cast structural unitfor a compressor, comprising means defining a cylinder and integral silencer chambers disposed laterally thereto, an integral dividing wall extending laterally from said cylinder, said silencer chambers extending in opposite directions from said wall on either side of said wall and opening outwardly in opposite directions therefrom. V

, 2. A structural unit as defined in claiml, wherein at least two silencer chambers are provided on at least one side of said wall.

3. A structural unit as defined in claim 2, wherein one chamber on one side of the wall at least partially overlaps two chambers on the other side of the wall.

4-. A structural unit as defined in claim 1, wherein said wall is formed with a connecting bore and a tube is disposed therein having a length greater than the thickness of the wall.

5. A structural unit as defined in claim 1, further comprising an integral extension provided with a connection bore, said extension being disposed adjacent the chamber wall just below its frontal surface.

6. A structural unit as defined in claim 1, wherein the structural unit is cast in one piece with a motor mount for the driving motor.

7. A structural unit as defined in claim 1, wherein the open ends of all of the chambers on one side of said wall are sealed with a common cover plate.

3. A structural unit as defined in claim 7, wherein plates are attached on opposite sides of the structural unit and said plates are secured by common securing means.

9. A cast structural unit for a compressor, comprising means defining a'cylinder, an integral dividing wall portion extending laterally from said cylinder approximately parallel to the axis of said cylinder and means defining a set of integral silencer chambers comprising chambers disposed on opposite sides of said dividing wall and opening outwardly in opposite directions therefrom and means defining passageways interconnecting said chambers.

19. A cast structural unit for a compressor comprising a block having a first face, a second face approximately parallel to said first face, a third face approximately perpendicular to said first and second faces, a portion defining'a cylinder disposed between said first and second faces and opening in said third face, integral dividing wall portions extending laterally from opposite sides of said cylinder and disposed between said first and second faces and integral silencer chambers disposed on opposite sides of said dividing wall portions and opening respectively in said first and second faces and means interconnecting said chambers.

11. A structural unit as defined in claim 10, in which one chamber on one side of said dividing wall portion overlaps two chambers on the opposite side of said dividing wall portion and in which said interconnecting means comprises passageways opening from both of said two chambers into said one chamber.

12. A cast structural unit for a compressor comprising a block having a first face, a second face approximately parallel to said first face, a third face approximately perendicular to said first and second faces, a portion defining a cylinder disposed between said first and second faces and opening in said third face, an integral dividing'wall portion extending laterally from said cylinder and disposed between said first and second faces and integral silencer chambers disposed on opposite sides of said dividing wall portion and opening respectively in said first and second faces, said chambers comprising two chambers on one side of said dividing wall portion and one chamber on the opposite side of said dividing wall portion overlapping saidtwo chambers and passageways approximately perpendicular to said first and second faces opening from said two chambers into said one chamber.

13. A casting for use on a compressor for providing a cylinder and silencer chambers in a single structural unit comprising means defining an open-ended bore, for use as a cylinder in operation, integral dividing wall portions extending symmetrically, laterally from said cylinder substantially parallel to a longitudinal axis of said cylinder, to define two sets of integral chambers for use as silencer chambers in operation, each set comprising chambers disposed on opposite sides of said wall portions and having one end opening outwardly, and means including said 5 Wall portions defining passageways providing communication between the chambers of a given set.

14. A casting according to claim 13, in which said sets comprise two sets each comprising a plurality of silencer chambers, and said sets being disposed symmetrically relative to said cylinder.

15. A casting according to claim 13, in which each set comprises an odd number of silencer chambers.

16. A casting according to claim 13, in which the cylinder chambers extend substantially normal to said cylinder, each chamber having an axial length less than the length of a portion of the casting in which they are disposed.

17. A casting according to claim 13, in which at least some of said silencer chambers are disposed in said sets in at least partially overlapping positions on opposite sides of respective ones of said wall portions.

7 References Cited by the Examiner UNITED STATES PATENTS DONLEY I. STOCKING, Primary Examiner.

15 LAURENCE V. EFNER, KARL J. ALBRECHT,

Examiners. 

1. A CAST STRUCTURAL UNIT FOR A COMPRESSOR, COMPRISING MEANS DEFINING A CYLINDER AND INTEGRAL SILENCER CHAMBERS DISPOSED LATERALLY THERETO, AN INTEGRAL DIVIDING WALL EXTENDING LATERALLY FROM SAID CYLINDER, SAID SILENCER CHAMBERS EXTENDING IN OPPOSITE DIRECTIONS DROM SAID WALL ON EITHER SIDE OF SAID WALL AND OPENING OUTWARDLY IN OPPOSITE DIRECTIONS THEREFROM. 